I'm not a big fan of "revisionist history," especially where Star Trek is concerned (which is why I usually hate prequels done after the fact, like ENT.) And these movies had revisionist history in spades.
GEN: Guess what? We find out that, instead of Kirk dying normally in the course of time, he was actually whisked away to the 24th century where he cooks eggs, meets Picard, pines over some woman we've never heard of before, and dies in the most contrived way possible. Oh, and there's this Nexus thingy that we're only just learning about now but Guinan knew about the whole time and never told Picard, despite their long and trusted friendship, and the effect the Nexus had on her life.
FC: Guess what? We find out that the Borg are now controlled by some individual, horny queen bee, even though Picard should have known this when he was Locutus, never mind that we've never seen this queen before. So instead of actions dictated on pure logic, the Borg now do what queen bee wants. And guess what else? We find out that Zefram Cochrane, inventor of the human warp drive, was really just some old drunk asshole in some hick town who built warp drive to get rich and fuck girls. Which was the complete opposite of how he was portrayed in TOS.
INS: Guess what? Not exactly revisionist history per se, but we find out that the Enterprise crew have no problems disobeying the direct orders of Starfleet Command and making a mini-insurrection to save a few people because a planet that isn't even theirs is being stolen to use to help save untold billions of people instead of finding a more logical way to deal with the problem.
NEM: Guess what? We learn all kinds of shit we never knew before! All this time Picard had a clone! But we aren't actually sure why. For the last several hundred years, Romulus's sister planet was inhabited by evil space vampires! Even though this is the first time they're ever mentioned or seen despite seeing Romulans many times in TOS and TNG. Data has yet another brother! Even though we don't know how it came into Shinzon's possession. Would Dr. Soong really be that careless? We learn that Picard has always wanted to be like Mario Andretti! Even though Picard as depicted in TNG would never have been interested in that, especially considering the fact that ground vehicle usage is a thing of the past.
TFF: Guess what? Spock has a half-brother that he knew about all along but never told anyone! (Sorry, it was too good to pass up.)